morrison



2 Sheets-Sheet 1. J. B. MORRISON.

ADJUSTABLE CHAIR.

No. 369,296. Patented Aug. 30,1 87.

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2 SheetsSheet 2.

J. B. MORRISON.

ADJUSTABLE 0mm.

No. 869,295. Patented Aug. 30, 1887.

nrrnn STATES Parana Orri-cnt JAMES B. MORRISON, OF KANSAS CITY, MISSOURI.

ADJUSTABLE CHAIR.

SPECIFICATION forming part of Letters Patent No.369,295, dated August 30, 1.887.

Application filed January 5, 1875.

Z?) aZZ whom it may concern.-

Be it known that I, Janus B. Monnisow, of Kansas City, in. the county of Jackson and State of Missouri, formerly of the city of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Adjustable Chairs, of which the following is a specification.

The present invention relates more partied larly to that class of adjustable chairs which are designed for dental purposes, and more especially to improvements in the chair for which Letters Patent of the United States were granted to me September 29, 1868, No. 82,542.

The present invention relates to the construction of the chair with legs or supports which are adj ustable automatically and independently of each other, whereby the chair is caused to adjust itself to irregularities of the floor; to a novel means forsecuring the tilting upper frame of the chair, which sustains the seat at the desired inclination; also, to peculiardcvices for adjusting the baelerest forward and backward; also, to a shoulder-rest adapted for adjustment upward, downward, and sidewise independently of the main backrest, and also capable of being removed at pleasure independently of the other parts; also, to a supplemental or secondary footrest capable of being turned forward and backward with respect to the main foot-rest, so as to be presented in an operative position nearer to or farther from the seat, as may be required by patients differing in their length of limb.

Referring to the accompanying drawings, Figure 1 is a side elevation of an adjustable chair embodying my improvements. Fig. 2 is a rear elevation of the same with a portion of the main hack-rest broken away to expose the means for adjusting the shoulder-rest. Fig. 3 is a central vertical longitudinal section of the chair. Fig. dis a back View, on an en largcd scale, of the mechanism at one side of the chair, for adjusting the back-rest and for securing the same at the desired inclination. Fig. 5 is a transverse section, also on an enlarged scale, of said adjusting mechanism, the section being taken on the plane of the dotted line a: 0;, Fig. 4. Fig. 6 is a side elevation, partly in section, of the mechanism by which the framework of the chair-body may be se cured at the desired inclination irrespective of the adjustment of the various parts carried thereby. Fig. 7 is an end view of the mechanism last referred to. Fig. 8 is a side view of the supportingframe, illustrating the manner in which the chair adapts itself to irregularities of the floor.

The frame of my chair consists of a base portion or pedestal, and of tilting standards adj ustably secured thereon. The standards are in turn provided with an adjustable frame, to which the seat and footrest and the sectional back and head rest are attached, as hereinafter explained.

The base or pedestal consists in the example shown of two side frames, A A, each having two legs or feet, 66 and b, to rest upon the floor, the feet being usually provided, as shown, with rollers or casters. The two side frames are elevated at a point between their feet, and are connected at or near the top by a crossrod, B, on which they are permitted a pivotal action independently of each other. These two side frames thus connected constitute the base or pedestal of the chair, the peculiarity of which lies in the fact that when placed upon a floor or other surface which is irregular the independent motion of the two frames permits their fourfeet to rest firmly upon the said surface.

Below the connecting rod or shaftB the baseframes A are provided with a slot, 0, concentric with the rod, and in these slots are seated the extremities of the rock-shaft D, free to slide forward and backward therein for the purpose which will be presently explained.

E E designate two parallel standards or bars, which are shown as connected together by stretchers or cross-bars F F. These standards are pivoted on the cross-shaft B, in order that they may be tilted forward and backward and thus placed at different inclinations. Their lower extremities are mounted on the ends of the rockshaft D. On each end of the shaft D is mounted a loose friction-plate, G, having its outer surface arranged to bear against the adjacent base-frame and its inner surface inclined or made of a cam shape. The shaft is also provided on each end with a fixed collar, G, having its outer surface made of a cam shape and arranged to bear against the loose collar. The loose collar is provided with a point or projection entering the groove in the base-frame, whereby it is prevented from rotating. The result is that upon turning the rock-shaft in the proper direction the frictionplates G are forced outward firmly against the base-frame, and thus caused to lock the rockshaft in position, the shaft in turn holding the lower ends of the standards and maintaining them at the inclination to which they may have been previously adjusted. The outer end of the rock-shaft is provided with, a lever, H, which may be conveniently operated by the foot of the attendant. By means of this lever the attendant is able to secure or release the standards, his hands being left free in the meanwhile to effect their adjustment.

K represents the upper adjustable frame,by which the seat and various rests are sustained. It consists of side frames or plates of the form shown, arranged to slide upward and downward on the standards E, mechanism of any suitable form being provided to effect this adj ustment. The means represented in the drawings consist of pinions I, mounted on a shaft on the frame and engaging in racks J on the standards in the manner described in my Letters Patent before named. A pawl, t, mounted on the frame and engaging with aratchetwheel, j, on the pinion-shaft,serves to lock the pinions and sustain the frame in position.

L designates the seat of the chair, which in the present instance is fixed firmly in position on the frame.

M designates arm-rests arranged at the sides of the seat, in the present instance in such manner that they may be adjusted vertically with respect to theseat in the same manner as in my original patent.

N designates the main back-rest, which is capable of bodily adjustment forward and backward, and also of an adjustment to different angles or inclinations. The adjustment of the rest may be effected by various means the equivalents of those herein described and shown. In the present instance it is loosely connected near the top by cords or other equivalent means to the chair-frame K, and near its lower end is provided with backwardlyextending internally-toothed arms I, which engage with pinions f on a shaft, 0, j ournaled horizontally across the back of the chair-frame K. By properly turning the shaft, which is provided with a hand-wheel or similar device at one end, the lower edge of the back may be advanced or retracted. As one convenient means of locking the back forward in the required position, I employ a lever, Q, pivoted to one end of the shaft 0, and having a bent end, which may be engaged with one of the arms P.

R designates a shoulder-rest capable of independent adjustment upward and downward and sidewise. This shoulder-rest, which constitutes in effect a portion of the back of thechair, is shown as secured to a bar, '1, which is slotted vertically for a portion of its length and guided by means of a pin, 70, and screw 1,

passing through said slot and into the frame,

thus permitting the bar to be raised and lowered, in order to effect the vertical adjustment of the shoulder-rest. The screw Z is passed not only through the bar, but also through a horizontal slot in the frame K, whereby it is permitted to play laterally, in order that the bar T and the shoulder-rest may be moved sidewise. On tightening the screw Z the bar and rest are fastened in position. The shoulderrest R is secured to the bar T by means of a thumb-screw, 8,, passing through the slot in the bar, as shown, whereby the shoulder-rest is permitted to slide bodily upward and downward with respect to the bar, and also permitted to rock or tip sidewise, as may be required. The bar T, on which the shoulderrest is carried, has its upper end extended backward horizontally, to give support to a head-rest, S. This head-rest has on its under side a plate of spheroidal form seated ina corresponding plate, S, which is confined in position by means of a bolt, 8, which, is extended downward through a horizontal slot in the supporting-arm T, and secured by a nut on its under end. This connection permits the I head rest to be revolved horizontally around the bolt, to be moved forward and backward horizontally by the movement of the bolt lengthwise of the slot, and also to be tipped freely in all directions by the movement of its spheroidal support in the corresponding plate, S.

It will be perceived that the back of my chair is composed of a plurality of restsnamely, the main back-rest and the head-restwhich are detachable independently of each other. The usual foot-bar or foot-rest of the chair is provided with a supplemental foot bar or rest, U, supported by arms which are connected to the main rest by horizontal pivots n. The pivotal connection permits the rest to be turned forward in position for use, as shown in full lines in Figs. 1 and 3. It also admits of its being tipped or turned backward upon its pivot to a position near the seat, as

indicated by dotted lines in Fig. 3, for the use of children and other patients short of limb.

Upon the upper surface of the main foot-rest V are placed near the outer edge, and upon opposite sides and extending from front to rear at a gradual elevation, the inclined portions or planes m- I then attach to the opposite arms of the foot-rest, above the pivots n a, the cross-bar t, which rests upon the inclined plane on, and as the rest is carried toward the chair-seat from the end of the main foot-rest the changes of inclination take place.

I am aware that a school-seat'has-been provided with two supporting-frames attached thereto by curved sliding joints, and each secured independently of the other by a bolt, and to such construction I lay no claim. It will be perceived that my base-frames are attached to the upper frame by a single pivot, thus giving an easy and noiseless action and IOC avoiding the expense which would attend the fitting of sliding joints. Itwill be further observed that in my chair the two independent base'frames are secured by a single locking device.

I am aware that a rockingchair has been provided beneath its seat with a forwardlysliding frame to which a foot-rest was attached by pivoted arms, the construction being such that the foot-rest had but a single operative position, and that when. its arms were turned rearward they would close within the sliding frame, and to such organization I lay no claim. My structure differs there from, first, that it has a foot-board or platform distinct from the foot-rest; second, the pivoted rest-supporting arms interlock with the supporting-frame in two operative positions, one when they are turned forward and the other when they are turned backward.

It is to be noted that, as regards the supplemental foot-rest, myinvention has special reference to dental chairs the seats of which are adjusted to different heights and positions, and which are provided necessarily with a step or platform connected with the seat or seatframe, so that the patient may step thereonin moving to and from the chair. The supple mental foot-rest which I provide is used in connection with this step or platform, and is movable to and from the seat of the chair, in order that it may be adjusted to adapt the chair for patients differing in their length of limb.

I do not claim to be the first to provide a chair with an adjustable foot-support; but I believe myself to be the first to provide a dental chair having a step or platform connected to the seat-frame with a supplemental adjustable foot-rest.

Having thus described my invention, what I claim is- 1. In a dental chair, the combination, substantially as described, of the upper or main frame, the legs united thereto by horizontal pivots and movable independently of each other, and a locking mechanism independent of the pivots to unite the frame and legs.

2. In a dental chair, the upper or seat-sustaining frame, in combination with the legs pivoted thereto and movable independently of each other, and a locking mechanism, substantially as described, provided with an operatinglever, whereby the operator is enabled to instantly lock and unlock the frame to permit its change of inclination while in use.

3. In combination with the base-frame A, provided with slots G, the chair-frame pivoted thereon, the standards E, rock-shaft D, friction-plates G, cams G, and lever II.

4. In combination with the supporting-frame and the back-rest provided with internallytoothed frames, the pinions f, mounted on the supporting-frame and operating with the teeth, as described.

5. The combination, with a dental chair,

substantially as herein described and shown,

of the main frame, the head-rest, the back-rest,

and the shoulder-rest, with means, substantially as described, for adjusting and securing each of said rests independently of the others.

6. In a dental chair, the combination, with the main supporting-frame having aseat thereon and a main back-rest, of the shoulder-rest removably secured to and adj nstable laterally at an angle of inclination to and independently of the said main back-rest.

7. In a dental chair, the combination, substantially as herein shown and described, of the supporting-frame and a seat thereon, the adj nstable head-rest and a bar secured to said frame, and having a vertical and lateral adjustment in relation thereto, and an adjustable shouldenrest secured to the said bar and detachable independently of the said head-rest, for the purpose described.

8. In a dental chair, aseat-snpporting frame having a step or platform sustained thereby, in combination with a supplemental foot-rest sustained by said platform and adjustable in relation thereto to and from the chair-seat to different operative positions, whereby the said rest is enabled to sustain its relation to the seat notwithstanding change of position.

9. In combination with a chair-bod y having a platform or step attached thereto, a supplemental foot-rest, and arms to sustain said rest pivoted to the platform to swing forward and backward to alimited extent and interlocking with said platform in an upright operative position when turned rearward as well as forward, whereby said arms are adapted to sustain the rest in either of two operative positions at different distances from the chair-seat.

10. In combination with the platform or steps having slots p, the adjustable supplemental foot-rest U, connected thereto by pivots n, entering said slots, as described and shown, and inclined bearing-surfaces on said platform supporting the said footrest, and a cross-bar attached to said arms above said pivots, whereby said foot-rest is permitted to tip forward and backward into different operative positions, and also permitted to slide horizontally to and from the chair.

11. A chair, a platform or step attached to its seat-frame having slots receding from front to rear, an adjustable supplemental foot-rest, U, connected thereto by pivots entering said slots, substantially as described, and inclined bearing-surfaces on said platform supporting the said foot-rest, and a cross-bar attached to said arms above said pivots, whereby the said rest is enabled to slide bodily to and from the seat, and also adapted to swing on its pivot to different operative positions.

JAMES B. MORRISON.

"Witnesses:

T. J. KEANE, A. J. Dn LAGEY.

ICO 

